A device is provided for inspecting an installed electrical system including a power panel and branch circuits with respective circuit breakers. The device includes a power interface unit with a Ground Fault Circuit Interrupter (GFCI) for connection with the power panel. Further, the device includes a power source for temporarily powering the electrical system through the GFCI. For safety purposes, the device allows the energized GFCI to be closed only when the device and the power panel are connected. Moreover, the device provides for selective closing of the circuit breaker of an individual branch circuit to test a power response thereof to indicate whether the individual branch circuit has a fault therein.